ClassInstance

java连接elasticsearch7.x版本跟6.x有很大不一样，api都改了不少。废话不多说，直接分享代码，让看到的人少掉坑里。

由于我开启了xpack密码验证，所以连接es时也要加上密码，代码如下：

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.http.HttpHost;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestClientBuilder.HttpClientConfigCallback;
import org.elasticsearch.client.RestHighLevelClient;

public class EsUtil {

	public static RestHighLevelClient getClient() {
		/** 用户认证对象 */
		final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
		/** 设置账号密码 */
		credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials("elastic", "123456"));
		/** 创建rest client对象 */
		RestClientBuilder builder = RestClient.builder(new HttpHost("127.0.0.1", 9200))
				.setHttpClientConfigCallback(new HttpClientConfigCallback() {
					@Override
					public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
						return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
					}
				});
		RestHighLevelClient client = new RestHighLevelClient(builder);
		return client;
	}
	
	/**
	 * 单条保存  
	 * @param index
	 * @param id
	 * @param m
	 */
	public static void saveData(String index,String id,Map<String, Object> m){
		try {
			RestHighLevelClient client = getClient();
			
			IndexRequest indexRequest = new IndexRequest(index)
			    .id( id)
			    .source(m);
			client.index(indexRequest, RequestOptions.DEFAULT);
		} catch (Exception e) {
			e.printStackTrace();
		}
		
	}
	
	public static void main(String[] args) {
		Date d = new Date();
		String id = d.getTime()+"";
		
		Map<String, Object> m = new HashMap<String, Object>();
		m.put("id", id);
		m.put("area_id", 1);
		m.put("camera_id", 1);
		m.put("log_time","2019-08-01 11:11:11");
		m.put("age", 1);
		EsUtil.saveData("global_house_list",id,m);
	}
}

		<dependency>
			<groupId>org.elasticsearch.client</groupId>
			<artifactId>elasticsearch-rest-high-level-client</artifactId>
			<version>7.1.0</version>
		</dependency>
 		<dependency>
			<groupId>org.elasticsearch.client</groupId>
			<artifactId>elasticsearch-rest-client</artifactId>
			<version>7.1.0</version>
		</dependency>
		<dependency>
			<groupId>org.elasticsearch</groupId>
			<artifactId>elasticsearch</artifactId>
			<version>7.1.0</version>
		</dependency>

但是测试时getClient这个方法可以这样写，生产环境中，我们不可能一直new Client，这样效率很慢，所以需要将连接好的client存在内存中，减少不必要的生成client对象，将上面的getClient()方法修改单列如下：

	//每次都取client太耗时，大约需要2秒左右，所以只取一次，放在内存中，不关闭，一直用
	private static RestHighLevelClient client  = null;
	
	public static RestHighLevelClient getClient() {
		try {
			if(client != null){
				return client;
			}
			synchronized (EsUtil.class) {
				if(client != null){
					return client;
				}
				long t = new Date().getTime();
				
				/** 用户认证对象 */
				final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
				/** 设置账号密码 */
				credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials("elastic", "123456"));
				/** 创建rest client对象 */
				RestClientBuilder builder = RestClient.builder(new HttpHost("127.0.0.1", 9200))
						.setHttpClientConfigCallback(new HttpClientConfigCallback() {
							@Override
							public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
								return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
							}
						});
				client = new RestHighLevelClient(builder);
				long t1 = new Date().getTime();
				System.out.println("获得连接，耗时:"+(t1-t)+"s");
				return client;
			}
			
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}